Cyclic AMP and adaptive supersensitivity in guinea pig atria

Summary

Supersensitivity was induced by injection of guinea pigs with reserpine, 0.1mg/kg/day for 7 days. This treatment induced chronotropic supersensitivity of isolated right atria to isoproterenol but not to forskolin. The pretreatment induced supersensitivity to the cyclic AMP-generating effects of isoproterenol or forskolin in left, but not right, atria. These results are dis-cussed in reference to the extensive literature describing supersensitivity in the guinea-pig heart, including the possible role of the adenylyl cyclase system.